Various systems can utilize a power system to convert power as needed. Vehicle systems user power rectifiers to convert power in generation systems for distribution and use on the vehicle. Building systems use power rectifiers and converters of power systems to covert grid power for uses in elevator systems and large chiller systems utilize a power system to drive compressors and fan systems. Conveyance systems, such as elevator systems, use machines to impart force to a car carrying passengers. The machines employed may need to provide varying power levels depending on the application. When either an elevator system or a chiller system requires a large duty or load, a motor drive needs to be provided to power the machine. Likewise, power generation systems often need to convert large amounts of AC power to DC for a given application. Often, a high power system with a rectifier or converter of sufficient capacity may not exist, which results in high design costs and lengthy development time to manufacture a suitable system. Even if a single, large rectifier or converter exists in the marketplace, costs associated with a single, large unit may be excessive due to specialty components, component availability, etc. Also, high power rectifiers and converters commonly require expensive high voltage components. Therefore, paralleling or multilevel configurations may provide a more cost effective approach.
Commonly, power systems can employ active or passive rectifiers to generate a DC bus and then an inverter scheme to drive the motors. This is done to improve performance of the power system in particular for variable speed or variable capacity systems. However, a variety of architectures may be employed for power rectifiers and converters to provide the best efficiency and reliability in the power system. For example in some embodiments, an independent rectifier may be employed to drive a load or a plurality of loads. Series, stacked, or multilevel configurations can be advantageous for high voltage applications while avoiding high stress levels on components. Similarly, paralleled configurations can provide for increased load capabilities while also reducing conduction stresses on components. Identifying the advantages and disadvantages of various topologies can sometimes be difficult based on timing and switching of power, electromagnetic interference (EMI), and the like. Evaluating various configurations and topologies for power systems and particularly rectifiers and converters facilitates selecting the most advantageous configuration for a given application.